Insulating composition



"106. COMPOSITIONS,

comma on msnc (r088 Reference Patented Sept. 20, 1932 UNITED STATESPATENT OFFICE LAURENCE E. POWER, OF MILWAUKEE, WISCONSIN, .ASSIGNOR, BYMESNE ASSIGN- MENTS, T ALLEN-BRADLEY COMPANY, OF MILWAUKEE, WISCONSIN, ACORPORA- TION OF WISCONSIN INSULATING COMPOSITION sulating lining isobtained at a considerably No Drawing. Application filed May 5,

This invention relates to certain new and useful improvements ininsulating composireduced cost. tions and method of making the same, andThe insulating composition is formed by refers more particularly toinsulating comcombining two colloidal solutions which have Examinerpositions for use as linings of electrical conthe charactertistics ofthickening immediate- 55 troller housings, or cabinets; and is a conlyupon contact with each other. The ingretinuation as to all commonsubject matter of clients of the two solutions are glue water anapplication filed September 29, 1926, Seand powdered mica for one, and asolution of rial No. 138,494. sodium silicate (water glass) as theother.

Heretofore, the walls of metal cabinets and These ingredients are in thefollowing pro- 60 housings for electrical apparatus have been portions:protected by gluing sheet asbestos or the like Parts thereto, but thismethod is objectionable in Glue 7 that asbestos paper is not onlyexpensive, but Water; 20

is costly to apply, and further its resistance Mica 5 65 to an electricarc is very unsatisfactory. odium silicate 5 It is therefore, an objectOf this invention Ordinary commercial grade) to provide an improvedinsulating composition which is comparatively cheap, easily applied as alining for cabinet walls, and which offers excellent resistance to thedestructive forces of an electric arc.

Another object of this invention resides in the novel method of makingthe insulating composition, whereby an immobile substance is formed by acolloidal precipitation in two fluids brought together at the time ofapplication.

And a further object of this invention resides in the formation of animmobile insulating composition of two solutions having thecharacteristic of thickening immediately upon contact with each other.

The present conventional manner of insulating the interior wall surfacesof metal cabinets for switches and other electric apparatus, is to linethe same with asbestos and have been found from experience to withstandthe arc test in a very satisfactory manner, and will not show a tendencyto run during application, irrespective of the inclination of thesurface.

The proportions given above may be varied considerably and still produceexcellent results, as it is difficult in actual practice where thematerials are sprayed separately, to maintain the exact proportionsbetween the glue, water and mica and sodium silicate. It is desirable,however, to avoid a large excess of sodium silicate over that which isnecessary to produce the desired increase in viscosity, as sodiumsilicate is not a good insulator at high temperatures.

The glue employed in the above solution is formula a or. While thismanner of lining cabinets hasbeen in vogue for many years and meets $3,3 glue-16 to 18 cent grade" with the approval of the board of under-Glucose 20 writers, it is open to many serious objectio s G1 Germ; 30such as the inability of asbestos paper to g g'g "a 8 satisfactorilyresist an electric arc and also that it is very expensive to apply, bothfrom the standpoint of material and labor.

This invention. therefore, contemplates the elimination of thecumbersome manner of lining cabinets heretofore used, by applying animproved insulating composition directly to their interior walls,wherein a better inalthough it is to be understood that any glue capableof providing the necessary adherence may be used. The mica employed ispreferably a 200 mesh.

In forming the glue solution, the glue and water are first mixed andthen the powdered mica is thoroughly stirred therein.

preferably made according to the following/ a If it is desired to applythe composition by means of a brush, its viscosity, which increasesimmediately with the combining of the two solutions due to aprecipitation of colloids, may be lowered by heating the same to aworking temperature somewhere in the neighborhood of 160 degreesFahrenheit.

However the more preferable method of applying the composition is tospray the two solutions simultaneously so that the two streams meet andco-mingle just prior to striking the surface being coated.

This manner of application greatly facilitates the lining of thesurfaces as the solutions retain their fluid state until the actualapplication. Any manner of spraying the solutions may be employed butthe method described in a copending application Serial No.

388,542, filed August 26, 19:29, is deemed preferable. As described, inthis application, two conventional spray guns are connected in such amanner that the sprays emitted therefrom meet at a point slightly spacedfrom the guns, each gun being connected with a receptacle containing onesolution.

From the foregoing description it will be readily apparent to thoseskilled in the art to which an invention of the character describedappertains that I provide an improved insulating composition which maybe very economically and effectively applied to a wide variety of uses,and which provides an insulation capable of withstanding destructivearcing forces.

What I claim as my invention is:

1. An insulating composition comprising a precipitate of seven partsglue, 20 parts water, five parts mica. and sodium silicate.

2. An insulating composition comprising a precipitate of seven partsglue, twenty parts water, five parts mica, and five parts sodiumsilicate.

3. An electrical insulating composition capable of withstanding hightemperatures without damage, comprising the precipitate of a mixture ofglue including animal glue, glucose, glycerine and soluble oil, waterand mica, with sodium silicate.

In testimony whereof I have hereunto affixed my signature.

LAURENCE E. POWER.

